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Revision Notes

Circle

ICSE · Class 9 · Mathematics

Quick revision notes for Circle — ICSE Class 9 Mathematics. Key concepts, formulas, and definitions for last-minute revision.

43 questions20 flashcards5 concepts

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A labeled diagram illustrating the fundamental components of a circle, including the center, radius, diameter, chord, and circumference.
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Key Topics to Revise

1

Basic Definitions and Components

  • A circle is the locus of all points in a plane that are at a fixed distance from a fixed point
  • The fixed point is called the centre and the fixed distance is called the radius
  • Circumference is the perimeter of the circle
2

Special Types of Circles and Polygons

  • Concentric circles have the same centre but different radii
  • Equal or congruent circles have equal radii
  • A circumscribed circle passes through all vertices of a polygon
3

Arcs, Segments, and Sectors

  • An arc is a part of the circumference of a circle
  • Minor arc is smaller than semicircle, major arc is larger than semicircle
  • When both arcs are equal, each is called a semicircle
4

Chord Properties and Theorems

  • Theorem 22: A line from centre to bisect a chord (not diameter) is perpendicular to the chord
  • Theorem 23: A perpendicular from centre to a chord bisects the chord
  • Greater chord is closer to centre, smaller chord is farther from centre

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Full Notes

Key Concepts

A circle is a closed curvePoints can be classified asConcentric circles have the same centreArc is part of circumferenceTheorem 22

Frequently Asked Questions

What are the important topics in Circle for ICSE Class 9 Mathematics?
Circle covers several key topics that are frequently asked in ICSE Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Circle — ICSE Class 9 Mathematics?
Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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All 28 chapters — ICSE Class 9 Mathematics Revision Notes

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